LIP and ROS in K562 cells.

(A) Determination of LIP in K562 cells. After quenching of non–cell-associated CA fluorescence by anti-CA antibodies, the permeable chelator SIH was added (arrow), and LIP was determined as specified in 2 from the stabilized signal attained after its addition. Cell incubations before LIP determination: (-·-·-), 48 hours, no ODN added; (–··–··–), 48 hours with 1 nM IN-ODN; (-----), 48 hours with 1 nM ASH-ODN; (·····), 48 hours with 1 nM ASL-ODN; (———), 48 hours with 1 nM both ASH-ODN and ASL-ODN. Bars represent the μM concentrations of calcein in the cells after the addition of the chelator SIH. (B) Determination of pro-oxidant prompted ROS formation in K562 cells. ROS production was determined based on the rise in fluorescence in CDCF-DA-am–loaded cells, as described in detail in “Materials and methods.” H₂O₂ (5 μM) was used as the pro-oxidant and was added to the cells where indicated. Treatment annotations are the same as in panel A.